Unveiling the therapeutic significance of shikimate pathway-derived phenolic acids against penicillin-binding protein 3 of Pseudomonas aeruginosa

Abstract

This study investigated the modulatory potential of Shikimate pathway-derived phenolic acids against penicillin-binding protein 3 (PBP3) of Pseudomonas aeruginosa using computational and in vitro methods. The binding and inhibitory capabilities of 22 phenolic acids against the catalytic site of PBP3 were evaluated and revealed ellagic and chlorogenic acids as the top inhibitors, showing superior docking scores of −8.4 kcal/mol each compared to the standard, cefotaxime (−7.5 kcal/mol). Dynamics simulation of their PBP3 complexes indicated chlorogenic acid’s efficacy in inhibiting PBP3 (−33.65 kcal/mol) relative to cefotaxime (−30.10 kcal/mol), while interacting with key catalytically relevant residues. The quantum features analysis using DFT/B3LYP suggested chlorogenic acid’s superior reactivity and compatibility with the PBP3 active site. In vitro evaluation revealed an MIC of 200 mg/ml for chlorogenic acid and 0.8 mg/ml for cefotaxime against Pseudomonas aeruginosa ATCC 27,853, while their combination showed a synergistic action mechanism (FIC index of 0.5). These observations were validated in time-kill kinetics (gradual decrease in viable cells over 24 h). The study concludes chlorogenic acid as promising PBP3 inhibitor. Nonetheless, further studies could focus on the structural modification of chlorogenic acid to improve its pharmacokinetic properties and potential as an antibacterial drug candidate in vivo.